Machine for automatically assembling armature cores and commutators therefor

ABSTRACT

Feeding mechanism successively brings armature cores and commutators therefor to an assembly station where they are held in coaxial endwise spaced relationship and where rotation imparting mechanism brings each armature core and commutator pair into correct angular relationship. A ram then pushes the commutator axially towards the armature core with the terminal tangs on the commutator facing the core, and presses it onto the shaft thereof, moving the commutator through a die which straightens tangs that may be askew. The tank straightening die has a round hole that slideably accepts the commutator, and longitudinally extending circumferentially spaced parallel grooves that slideably accommodate the tangs. When the commutator reaches proper position on the armature shaft, and while still in the die, a tang-shaping member having circumferentially spaced parallel fingers, one for each tang, telescopes over the commutator, each finger moving along one of the grooves to engage under the tang therein and lift it into contact with the bottom of the groove.

United States Patent [72] Inventors Thomas L. Schuette Osseo; Melvin J. Straub, Minnetonka; Pierre Dumas; Peter F. Aurich, Minneapolis, Minn.

[211 App]. No. 801,084

[22] Filed Feb. 20, 1969 [45] Patented May 25, 1971 [73] Assignee Possis Machine Corporation Minneapolis, Minn.

[54] MACHINE FOR AUTOMATICALLY ASSEMBLING ARMATURE CORES AND COMMUTATORS THEREFOR 13 Claims, 32 Drawing Figs.

[52] US. Cl 29/33,

[51] Int. Cl H02k 15/02 [50] Field of Search 29/205, 205

[56} References Cited UNITED STATES PATENTS 2,270,472 1942 Poole et al 29/205X Primary Examiner--Andrew R. Juhasz Assistant Examiner-James F. Coan Attorney-Ira Milton Jones ABSTRACT: Feeding mechanism successively brings armature cores and commutators therefor to an assembly station where they are held in coaxial endwise spaced relationship and where rotation imparting mechanism brings each annature core and commutator pair into correct angular relationship. A ram then pushes the commutator axially towards the armature core with the terminal tangs on the commutator facing the core, and presses it onto the shaft thereof, moving the commutator through a die which straightens tangs that may be askew. The tank straightening die has a round hole that slideably accepts the commutator, and longitudinally extending circumferentially spaced parallel grooves that slideably accommodate the tangs. When the commutator reaches proper position on the armature shaft, and while still in the die, a tang-shaping member having circumferentially spaced parallel fingers, one for each tang, telescopes over the commutator, each finger moving along one of the grooves to engage under the tang therein and lift it into contact with the bottom of the groove.

SOURCE OF ARMATU RES MACHINE FOR AUTOMATICALLY ASSEMBLING ARMATURE CORES AND COMMUTATORS THEREFOR This invention relates broadly to machines for assembling parts of electric motors, and refers more particularly to a machine for assembling commutators which have circumferentially spaced terminal tangs at one end thereof, onto armature cores'of the type comprising a stack of laminations with circumferentially spaced winding receiving slots, solidly mounted upon a shaft. When properly assembled, the commutator and armature core are so oriented that the terminal tangs of the commutator are in predetermined relationship with respect to the winding slots of the armature core, both angularly and axially. This relationship may be such that for each winding slot there is a single terminal tang in line therewith, as in the assembly specifically illustrated herein; or there may be two or even more terminal tangs for each slot, depending upon the nature of the windings to be applied to the core. Also, the tangs are not necessarily in line with the winding slots, even where there is only one tang per slot.

The purpose and object of this invention is to provide a machine for automatically assembling commutators and armature core more efficiently, more reliably, and faster than heretofore possible, regardless of the numerical relationship between the winding slots of the armature core and the terminal tangs on the commutator.

It has been customary to press-fit the commutators onto the shaft of the armature. In the past (as shown for instance by US. Pat. No. 1,690,322) this was done manually by placing each armature core and its commutator in'an arbor press, in the correct angular orientation to one another, and then, by actuation of the arbor press, forcing the commutator onto the shaft of the armature. Needless to say, production rates by this method were quite limited.

Although there have been efforts prior to this invention to automate the assembly of armature cores and their commutators, all known earlier machines for this purpose left much to be desired. One of the principal objections to the known prior machines was their inability to satisfactorily cope with commutators on which the terminal tangs are bent askew or otherwise improperly disposed. As a result, many of the assembled units were defective and had to be rejected. By contrast, the machine of this invention has reduced the rate of rejects by 90 percent and has done so despite its unprecedented production rates of 600 to 700 assemblies per hour. To illustrate, in the past it was not unusual that as many as 50 out of I000 armatures would have to be rejected because of defective terminal tangs. This constituted a percent reject rate. The 90 percent reject rate reduction brought about by the machine of this invention, has reduced rejects to no more than 5 per 1000 annatures.

To a large degree, the very high production rates made possible by the machine of this invention result from the fact that the straightening and shaping of the terminal tangs of the commutator takes place while the commutator and armature core are being assembled-in other words, all operations upon both the commutator and the armature core are performed at one station in the machine. 7

To accomplish this objective, the machine of this invention has means for continuously and successively transferring armature cores and commutators from sources thereof to an assembly station in the machine where the commutators and armature cores are paired and, when thus paired, are rotated relative to one another to bring them into proper angular orientation with the terminal tangs of the commutator aligned with or otherwise properly disposed with respect to the winding slots of the armature core. This takes but a fraction of a second. The commutator core is then moved axially toward the armature core and pressed onto its shaft, and during this assembling operation the terminal tangs of the commutator are straightened and formed into hooks of uniform shape.

In the event one or more of the terminal tangs of the commutator have been deformed to the extent that they cannot be straightened and properly shaped, sensing mechanism which utilizes the tang-shaping means, initiates the functioning of a reject mechanism so that when the assembled annature core and commutator with the defective terminal tang or tangs leave the assembling station of the machine, it is shunted into a reject path, as distinguished from the path traveled by assemblies that are proper in all respects, and which may lead to other machines where additional operations are performed;

With these observations and objects in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings. This disclosure is intended merely to exemplify the invention. The invention is not limited to the particular structure disclosed, and changes can be made therein which lie within the scope of the appended claims without departing from the invention.

The drawings illustrate one complete example of the physical embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a perspective view of an armature core and commutator of the type the machine of this invention is designed to assemble into the rotor unit shown in FIG. 2;

FIG. 3 is an overall perspective view of the machine;

FIG. 4 is essentially a top plan view of the entire machine, some of its upper structure having been omitted for sake of clarity;

FIG. 4a is a detail sectional view through FIG. 4 on the plane of the line 4a-4a.

FIGS. 5, 6 and 7 are elevational views generally taken on the plane of the line 5-5 in FIG. 3, illustrating the mechanism by which the armature cores are successively and individually presented to the assembly station of the machine, the mechanism being shown in different positions in the succeeding views;

FIG. 5a is a detail sectional view through FIG. 5 on the plane of the line Sa-Sa;

FIG. 7a is a detail sectional view through FIG. 7 on the plane of the line 7a-7a;

FIGS. 8, 9 and 10 are detail views illustrating that part of the mechanism shown. in FIGS. 5, 6 an 7, by which an armature core at the assembly station is rotated to a position in which its winding slots are in a predetermined orientation with respect to a fixed vertical plane passing through the axis of the core;

FIGS. ll, 12 and 13 are vertical elevational views generally taken on the plane of the line 11-11 in FIG. 17, illustrating the mechanism by which a commutator is held at the assembly station in coaxial alignment with an armature core thereat, and by which the commutator is positively rotated into correct angular orientation with respect to the armature core, preparatory to being assembled therewith, said views illustrating the commutator rotating mechanism in different positions;

FIG. 14 is a perspective view of the commutator holding and rotating mechanism shown in FIGS. ll-l3, inclusive, and the die by which the tangs on the commutator are straightened as the commutator is press-fitted onto the shaft of the armature core, the die being shown displaced from its correct position for sake of clarity, and an armature core being illustrated in position to receive a commutator;

FIG. 15 is a perspective view of an armature core and commutator in the act of being assembled, and in broken lines illustrating the commutator holding structure and the tangstraightening die;

FIG. 16 is a perspective view of the assembled armature core and commutator and illustrating the mechanism by which the tangs are shaped;

FIG. 17 is a sectional detail view through the mechanism at the assembly station of the machine, said view illustrating an. armature core and its commutator in coaxial, axially spaced relation preparatory to being assembled;

FIG. 18 is a view similar to FIG. 17, illustrating most of the structure shown therein, but with the parts thereof in the positions they occupy directly after the commutator has been pressed onto the shaft of the armature core and before the tang-shaping mechanism has functioned;

FIG. 19 is a view similar to FIG. 18, but showing the parts in the positions they occupy when the tang-shaping mechanism has functioned;

FIG. 20 is a detail cross-sectional view through FIG. 18 on the plane of the line 20-20;

FIG. 21 is an exploded perspective view of part of the mechanism by which the commutator is pushed onto the shaft of the armature core, and part of the mechanism by which the tangs of the commutator are shaped;

FIG. 22 is a perspective view of the tang-straightening die and the basketlike support or holder in which the commutator sets while it is rotationally adjusted in preparation to being pushed onto the shaft of the armature core, attention being directed to the fact that in this FIG. 22 the parts illustrated are viewed from the direction opposite that of FIGS. l4, l and 16;

FIG. 23 is a fragmentary detail sectional view through FIG. 14 on the plane of the line 23-23;

FIG. 24 is a top plan view of a portion of the hopper or bowl in which a supply of the commutators is maintained for transfer to the assembly station of the machine;

FIG. 25 is a vertical sectional view through the commutator supply hopper, taken generally on the plane of the line 25-25 in FIG. 24;

FIG. 26 is a cross-sectional view through the sidewall of the commutator supply hopper, taken on the plane of the line 26-26 in FIG. 24;

FIGS. 27 and 28 are elevational views of the gate mechanism whichcontrols transfer of the commutators from the supply hopper to the assembly station of the machine, showing the same in different positions; and

FIG. 29 is a flow sheet depicting the successive operations which the machine performs.

Referring now particularly to the accompanying drawings in which like parts are identified by like reference characters, in

FIGS. 1 and 2 the numeral 5 designates generally an armature core of the type with which this invention is concerned, and which comprises a stack of laminations 6 firmly mounted upon a shaft 7. The stack of laminations has equicircumferentially spaced winding receiving slots 8 opening to its peripheral boundary surface, and insulating sleeves 9 embrace the portions of the shaft 7 adjacent to the opposite sides of the stack. Beyond one of these sleeves the shaft has swedged ribs 10 projecting from its surface to bite into the bore of a commutator 11 when the same is press-fitted onto the shaft.

The commutator 11, as is customary, comprises circumferentially spaced segments 12 solidly mounted upon a body of insulation 13 to collectively present a cylindrical surface upon which brushes ride when the armature is assembled in a dynamoelectric machine. Each of the segments 12 has a hooklike terminal tang 14 at the end thereof facing the armature core, there being one segment 12 and one tang for each of the winding slots 8, in the specific armature structure shown. However, as noted hereinbefore, and as is well known to the art, there may be two or even more commutator segments and terminal tangs for each winding slot.

Since the winding of armatures is done on automatic machines, it is important that the terminal tangs be properly shaped and correctly positioned with respect to the winding slots 8 and the cylindrical surface of the commutator. This requirement for proper positioning and shaping of the terminal tangs presents a most difficult problem, and in prior attempts to automate the assembly of commutators and armature cores this problem either proved to be an insurmountable obstacle, or it unduly limited production rates. By contrast, the machine of this invention not only straightens and properly shapes the terminal tangs, but does so in a most reliable and expeditious manner while the commutators are being assembled onto the armature cores, so that the straightening and shaping of the tangs requires practically no additional time. This significant advantage is gained notwithstanding the fact that the commutators are very haphazardly handled, it being understood that the commutators, like the armature cores, are produced on other machines and must be transported to the assembling machine of this invention.

With reference now directed particularly to the general overall machine shown in FIGS. 3 and 4, the assembly station where the actual assembly of the armature core and its commutator takes place is identified by the reference character S." The armature cores 5 reach this assembly station by rolling down a track 15 formed by two inclined rails 16 mounted upon a base 17 for adjustment toward and from one another to accommodate armature cores of different sizes. The base 17 constitutes part of the general frame structure of the machine.

The commutators 11 are dumped haphazardly into a vibratory bowl 20 from which they pass to a downwardly inclined track or chute 21 which leads to a vertical guideway 22 down which the commutators fall onto a basketlike support 23- FIGS. l114. The cross-sectional shape of the inclined track or chute 21 is such that the commutators are free to roll therealong. Accordingly, the bottom 24 of the track or chute has a depression 25 adjacent to one side thereof to accommodate the tangs 14. The receiving and discharge end portions of the inclined track or chute 21 are preferably covered.

The vibratory bowl 20, which is essentially a conventional piece of apparatus, has an upwardly inclined track 27 formed in its sidewall 28 onto and along which-the commutators crawl due to the vibratory action of the bowl. As they travel along the track 27, improperly positioned commutators are knocked off the track and only correctly positioned commutators reach the discharge port 29 of the vibratory bowl, through which they pass onto the inclined track or chute 21.

As shown in FIG. 26, the track 27 has a groove 30 adjacent to the sidewall 28, to accommodate the tangs 14 of commutators that are properly positioned on the track, and to assure proper disposition of the commutators on the track 27, deflectors 31 and 32 project into the bowl from its sidewall above the track. The deflector 31 will dislodge commutators that tend to pile one upon the other, and the deflector 32 coacts with a downwardly sloping portion 33 which extends for a distance along the length of the track 27 ahead of the discharge port, to dislodge commutators not properly positioned on the track.

As seen in FIG. 26, properly positioned commutators ride along the track 27 with their tangs in the groove 30 and also between the sidewall of the bowl and a guard rail 34. The rail 34 is removably supported from the sidewall of the bowl by brackets 35; the removability of the guard rail 34 and the manner of its securement enabling the structure to be adjusted to handle commutators of different sizes.

At the discharge port 29, a gate, indicated generally by the numeral 35, functions to successively transfer individual commutators to the feed track or chute 21, and through control of the opening and closing of the gate the advance of the commutators is timed to assure that a commutator will arrive at the assembly station of the machine in time to be paired with an armature core that arrived at the assembly station by rolling down the track 15. The gate 35 consists of a lever 36 mounted to swing about a fixed pivot 37 and having a sector-shaped plate 38 detachably fixed thereto. A notch 39 in the outer arcuate edge 40 of the plate accommodates only a single commutator so thatassuming the presence of a commutator in the notch 39rocking of the lever in the clockwise direction to its position shown in FIG. 28, results in the foremost of the row of commutators moving along the track 27 being transferred to the track or chute 21, while the next and succeeding commutators are held back by the curved edge 40 of the plate 38.

Rocking of the gate lever 36 in the opposite direction to its position shown in FIG. 27, enables the next commutator to I enter the notch 39 and be held thereby until the gate is again 

1. A machine for automatically assembling commutators with armature cores of the type comprising a shaft with a stack of laminations thereon, the stack of laminations having circumferentially spaced winding receiving slots and the commutators having circumferentially spaced terminal tangs at one end thereof, each of which must be in a definite location with respect to at least one of the winding receiving slots of the armature core and form a hook of predetermined shape overlying the cylindrical surface of the commutator, said machine comprising the combination of: A. feeding means for successively transferring commutator and armature cores, each from a source thereof, to an assembly station; B. receiving means at the assembly station for receiving and holding commutators and armature cores in coaxial paired relation with the end of the commutator at which its tangs are located facing but spaced from the armature core; C. pressure applying means operable upon a paired armature core and commutator being held by said receiving means to effect relative axial movement thereof towards one another, to thereby press the commutator onto the shaft of the armature core; and D. tang-straightening means positioned to be engaged by the commutator tangs during relative movement of the commutator and the armature core toward one another.
 2. A machine for automatically assembling commutators with armature cores of the type comprising a shaft with a stAck of laminations thereon, the stack of laminations having circumferentially spaced winding receiving slots and the commutators having circumferentially spaced terminal tangs at one end thereof, each of which must be in a definite location with respect to at least one of the winding receiving slots of the armature core and form a hook of predetermined shape overlying the cylindrical surface of the commutator, said machine having
 2. receiving means at the assembly station for receiving and holding commutators and armature cores in coaxial paired relation with the end of the commutator at which its tangs are located facing but spaced from the armature core,
 2. positioning means engageable with the coaxial armature core and commutator and operable to bring the same into such angular orientation relative to one another that the tangs and winding slots are in predetermined positional relationship, and
 3. pressure applying means operable upon the coaxial armature core and commutator to effect relative axial movement thereof towards one another to thereby press the commutator onto the shaft of the armature core, said pressure applying means including a pressure applying member constrained to reciprocate along a defined axis, said machine being characterized by: A. tang checking and shaping means coaxial with said reciprocably movable pressure applying member, comprising cooperating relatively movable members adapted to clamp the tangs of the commutator therebetween upon relative movement of said members in one direction while a commutator and armature core are in the grip of said pressure applying means, to sense the posture of the tangs with respect to the cylindrical surface of the commutator and to lift all of the tangs at least a predetermined minimum distance above the cylindrical surface of the commutator if none of the tangs has its free end bearing against the surface of the commutator; and B. impositive power means for effecting such relative movement of said coopErating members, whereby the movement thereof in said direction is arrested by any tang which has its free end bearing on the cylindrical surface of the commutator, to provide an initiating signal for actuation of reject mechanism, while completion of such relative motion lifts the tangs at least to said predetermined minimum distance above the cylindrical surface of the commutator.
 3. pressure applying means operable upon a paired armature core and commutator being held by said receiving means to effect relative axial movement thereof towards one another to thereby press the commutator onto the shaft of the armature core, said machine being characterized by: tang-straightening means positioned to be engaged by the commutator tangs during relative movement of the commutator and the armature core toward one another.
 3. The machine of claim 2, further characterized by tang-shaping means positioned to be coaxially aligned with a paired commutator and armature core at the assembly station, and operable upon actuation to engage the tangs on the commutator and impart a predetermined shape thereto.
 4. The machine of claim 3, further characterized by power-driven actuating means for said tang-shaping means, timed to effect operation of said tang-shaping means directly after the commutator has been pressed onto the shaft of the armature core and while the assembled commutator and armature core are still at the assembly station.
 5. The machine of claim 1, wherein said tang-straightening means comprises a die member with a hole therethrough of a size and shape to axially slidably accept the commutator, the boundary surface of said hole having circumferentially spaced longitudinally extending grooves of a size to slidably accommodate the tangs, and means mounting said die member in a position to lie between a paired commutator and armature core at the assembly station, so that during relative movement thereof towards one another, the commutator is pushed into the hole and the tangs move along the grooves and in so doing become centered with respect to planes containing the axis of the commutator and bisecting the attached ends of the tangs, and the maximum radial projection of the tangs from the commutator is defined by engagement of the tangs with the bottoms of said grooves.
 6. The machine of claim 2, wherein said tang-straightening means comprises a die member with a hole therethrough of a size and shape to axially slidably accept the commutator, the boundary surface of said hole having circumferentially spaced longitudinally extending grooves of a size to slidably accommodate the tangs, and means mounting said die member in a position to lie between a paired commutator and armature core at the assembly station, so that during relative movement thereof towards one another, the commutator is pushed into the hole and the tangs move along the grooves and in so doing become centered with respect to planes containing the axis of the commutator and bisecting the attached ends of the tangs, and the maximum radial projection of the tangs from the commutator is defined by engagement of the tangs with the bottoms of said grooves.
 7. The machine of claim 5, further characterized by tang-shaping means comprising an axially reciprocable sleeve coaxial with said hole in the die member and having circumferentially spaced parallel fingers projecting from one end thereof to telescope over the commutator and enter the grooves in the boundary surface of the hole behind the tangs upon axial advance of thE sleeve toward said die member, the inner surfaces of the fingers being positioned to ride upon the cylindrical surface of the commutator, and the ends of said fingers being wedge-shaped with the apex of the wedge at the inner surfaces of the fingers so as to engage under the tangs in the grooves and lift the same towards the bottoms of the grooves, whereby the wedge-shaped ends of the fingers and the bottoms of the grooves can coact to define the maximum distance the tangs project above the cylindrical surface of the commutator.
 8. The machine of claim 7, further characterized by power means for imparting axial movement to the sleeve, said power means being timed to advance the sleeve after the commutator has been pushed into the hole.
 9. The machine of claim 6, further characterized by tang-shaping means comprising an axially reciprocable sleeve coaxial with said hole in the die member and having circumferentially spaced parallel fingers projecting from one end thereof to telescope over the commutator and enter the grooves in the boundary surface of the hole behind the tangs upon axial advance of the sleeve toward said die member, the inner surfaces of the fingers being positioned to ride upon the cylindrical surface of the commutator, and the ends of said fingers being wedge-shaped with the apex of the wedge at the inner surfaces of the fingers so as to engage under the tangs in the grooves and lift the same towards the bottoms of the grooves, whereby the wedge-shaped ends of the fingers and the bottoms of the grooves can coact to define the maximum distance the tangs project above the cylindrical surface of the commutator.
 10. The machine of claim 9, further characterized by power means for imparting axial movement to the sleeve, said power means being timed to advance the sleeve after the commutator has been pushed into the hole.
 11. A machine for automatically assembling commutators with armature cores of the type comprising a shaft with a stack of laminations thereon, the stack of laminations having circumferentially spaced winding receiving slots and the commutators having circumferentially spaced terminal tangs at one end thereof which must be in predetermined positional relationship with respect to the winding receiving slots when the assembly is completed and form hooks of predetermined shape overlying the cylindrical surface of the commutator, said machine having
 12. Apparatus for assembling commutators having terminal tangs onto armature cores of the type having a stack of laminations fixed upon a shaft, comprising: A. armature core-holding means adapted to receive and hold an armature core in a definite axially fixed position; B. tandem arranged first and second slidably mounted carriages constrained to travel along a path parallel to the axis of an armature core held by said holding means; C. a commutator support on the first carriage to receive and hold a commutator in coaxial alignment with an armature core held by said holding means; D. a bored die member on the first carriage positioned to at all times be between the armature core-holding means and the commutator support with the axis of its bore coaxial with an armature core held by said holding means, the bore of the die member being of a size to accept the commutator and having circumferentially spaced longitudinally extending grooves in its wall to slidably accommodate the terminal tangs on the commutator; E. yieldable motion transmitting means connecting the carriages for travel in unison while permitting relative movement therebetween; F. power means connected with the second carriage to effect simultaneous advance of both carriages towards the armature core-holding means; stop means for interrupting the advance of the first carriage when the same has moved far enough to cause the shaft of an armature core held by said armature core-holding means to project through the bore of the die member; and H. a pusher bar on the second carriage operable upon continued advance of the second carriage after the advance of the first carriage has been interrupted to shove the commutator off its support, into the bore of the die member and onto the shaft of the armature core, the passage of the tangs along the grooves in the die member as the commutator moves into the die member straightening any tangs that may be askew.
 13. The apparatus of claim 12 further characterized by a tang-shaping sleeve telescoped over the pusher bar and having circumferentially spaced parallel fingers, one for each groove in the die member, to embrace a commutator in the die member and enter the grooves therein upon advance of the sleeve with respect to the pusher member and the die member, the extremities of said fingers being shaped to lift the tangs towards the bottom of the grooves and thereby shape the tangs, and power means to advance the tang-shaping sleeve with respect to the pusher bar and into the die member. 